Pyroelectric vidicons are presently being developed as a low cost alternative to mechanically scanning thermal imaging devices using arrays of cooled infrared detectors. A charge pattern is produced on the surface of the vidicon retina and is read out by the electron beam and neutralized within one frame. In order to obtain charge images and thus video signals for subsequent frames, the temperature pattern on the retina has to be changed between read-outs. Unless the operation of the pyroelectric vidicons is restricted to the imaging of moving objects, the image of incoming infrared radiation must be changed. Prior art pyroelectric vidicons use choppers wherein the charge image must be read out once for the open chopper and once for the closed chopper. Since the frame rate of a conventional television monitor is 30 frames per second, the displayed image will flicker at the rate of 15 cps. To eliminate flicker, the frame rate needs to be increased by a 50 to 100 percent, resulting in higher mechanical burden on the synchronized mechanical chopper.
The present invention comprises optical means of moving the infrared image across the retina and simultaneously stabilize the visible image on a monitor, such as a television.